In a letter to the prime minister, Caulfield warned that the results of the Brexit proposal agreed by the Cabinet on Friday would be a loss of support for the Conservative Party and “Prime Minister Corbyn [Labour Party leader.]”

Bradley echoed these remarks: “If we do not deliver Brexit in spirit as well as in name, then we are handing Jeremy Corbyn the keys to Number 10.”

Bradley and Caulfield follow David Davis and Boris Johnson, who quit their roles as Brexit secretary and foreign secretary within the space of 24 hours. Steve Baker also resigned as a junior Brexit minister.

In his resignation letter, Johnson said that Britain is “truly headed for the status of [EU] colony” under the prime minister’s proposed post-Brexit relationship with the European Union.

Under May’s proposal, the UK would stay wedded to the EU standards for the trade and goods and collect EU tariffs on the bloc’s behalf, in order to preserve frictionless trade and the open Irish border.

However, it would make new free trade deals with certain countries, like the USA, much less likely, and would leave the UK under some influence of the European Court of Justice.